Cooling apparatus fob intebwal-combustion engines



A. 1. MARSCHALL.

COOLING APPARATUS FOR INTERNAL COMBUSTION ENGINES. APPLICATION mio JULY 5. |918.

1,316,91 2. PatentedSept. 23, 1919.

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ADOLF J. MARSCHALL, 0F MADISON, WISCONSIN.

COOLING APPARATUS FOR INTERNAL-COMBUSTION ENGINES.

Specification et Letters Patent. Ilafentcd Sept. 23, 1919.

. Appllcationj filed July 5, 3.918. Serial No. 243,307.

To f// l/mn/ [t muy concern le it known that I, Anonr J, lwiiiscimm., a citizenot' the United States, residing at Madison. inthe 'county of Dane,y State of Wisconsin. have invented certain new and useful Improvements in Cooling Apparatus for lnternal-Con'ibustion' Engines; and I do hereby declare the following to be a full, clear. and exact description of the inveii tion. such as will enable others skilled in the art to which it appertains to make and use the same.

'lhis invention relates to cooling apparatus t'or internal coinbnstioii engines and has t'or its object to provide an ellicient cooling system which will do away with the, complication. inconvenience and frequent trouble miavoidablc with the water circulating sysyis eloggi ne.

tems now almost. universally employed in automobiles` aeroplanes, etc.

There are at present. as regards their cooling systems. two types of internal combustion engines on the market, known popularly as water-cooled and air-cooled engines. By t'ar the greater number of engines` particularly automobile engines, ai'e of the. watercooled type. ln 'fact,lso` t'ar as l am aware, there is on the market but. one make of aircooled automobile engine which has attained any substantial coinmei'cial success.

.lhe common water-cooled system comprises essentially a jacket surrounding the portions ol the cylinder walls which form the explosion chamber, a radiator of sufficient surface area to maintain the desired temperature ot' the water and a pump or other circulating device, Jfor maintaining the water in continuous circulation through the radiator and the' jacket.

This apparatus involves iractical ditliicul-` ties in that the radiator (ue to the large surface required and the cons tricted space permissible on an automobile, is necessarily of moreor less fragile construction and is therefore unavo'idably subject to leakage and Also.y the pump'is liable to become clogged and its driving mechanism adds to the complication of the, motor. Were the air cooling systeins heretofore in ilse geneially regarded a'ssatistactory. they would obviously replace the water cooling system, as these troublesome parts ai'e done, away with.

'lhe chiet' difliculties of air cooling are the' ditiiculty of obtaining suilicieiit 'adiating sui-tace without having an`over-thickness of .Y

metalV between the explosion chamber and the surface, of the radiating projections, and' the ditticulty` of niaintaiiiin a uniform circulation of air over the sur ace .of the cylinders so as to utilize the entire surface eiliciently and maintain the' cylinder walls atjan approximately uniform temperature' throughout.

By my invention I provide a cooling system in which I have incorporated' the advantages of both the water cooling andthe air cooling system in that I avoid the pump and radiator of the water. cooling system and at the same time provide a larger cool' ing surface and a uniform cooling of the c vlinder walls, tliereb correctin'g'tlie detects ot' the air coole motor.

In the acconilianyingdrawings I have. illustrated a referred embodiment oi' the invention in its application to an internal combustion engine of a standard four-cylin der type, and in said drawings,

Figure l'is a side elevation of such any,

engine equipped with 'my invention with certain parts shown in' section and broken away tor convenience of illustration;

`i l* ig. 2 is a transverse section through the engine shown in Fig. 1; and

Figs. 3 and 4 are dia vrammatic representations ot' possible modi cations of the structi-ire of Figs. l and 2. I

VReferring to the drawings, 1 indicates the internal combustion motor, here shown in outline only and with its operating parts removed, the motor com rising fou'i` cylinders, 2, mounted vertical y in aiow on theV crank case. Each cylinder4 comprises a piston 3, one of whicl'i is shown in its lowerniost position to indicate the extentof the explosion chamber between the upper surface of the piston and the top of the cylinder, 'which is the portion of the engine that must be cooled for the engine to be continuously' operated.

ln carrying out my invention l surround i the upper portion ot' the cylinders constituting the explosion chambers with a jacket 4 generally similar to the water jackets of ordinary water cooled motors.,F lnit preferably ot larger capacity, particularly over the tolps ot' the cylinders, as indicatedin Fig. 1. T ie jacketI may be cast. integral ,with the cylinders in the usual manner of water jackets, o1' the lower part only may be cast integral i expansion an with the cylinders, the upper part 5 for all the cylinders beinggformed in a separate piece and attached to the lower part, as indicated at 6. The jacket is fluid-tight and is normally filled or substantially filled with .Water' or some other substance which is liquid at the operating temperatures -of the engine. A vent or blow-off valve 19 is preferably provided at the top of the jacket to relieve excessive pressure in case the substance in the acket is heated above its boiling point.

To further increase the radiating capacity of the jacket its outer surface is provided with fins or ribs 7 the ribs preferably extendin vertically along the side walls of the casing' and longitudinally across the top to provide passages through which the air will be drawn by a suitableexhaust fan, the

casing of which is indicatedat 8. The exhaust fan 'is connected through a pipe, 9

with an outer casing or 'cover 10,surr ound ing the jacket 4 and supported on the engine in any suitable manner,l as forl instance by the brackets 11. The casing 10 is spaced vfrom the ribs of the jacket to allow a large volume of air to be readily drawn through the casing by the action of the fan.

The casing 10 may be of any desired con' struction, but is preferably formed with its upper portions hinged as indicated at 12 (F ig. 2) along the middle of the top to give ready access to the spark plugs, etc., of the motor inclosed therein.

The operation of my improved cooling system is as follows: The water or other liquid in the jacket 4 serves several purposes.

the first place, the Water absorbs the heat from the cylinder walls much more rapidly 'than air at the same temperature. In the second place, the water in circulation, due to its heating at 'the c hnder walls and cooling at the jacket Wal s, maintains a uniform temp@rature throughout, thereby obviating and the consequent uneven heat by convection and not by conduction,

the distance of the jacke`t wall from the-wall `of the cylinder is immaterial and the jacket wall will be so proportioned as to give van external surface suiii'ciently great for the air circulating system to provide the necessary heat absorbing capacity. j

The uniform temperature of the liquid in the jacket notcnly equalizes the heat absorption from the several cylinders, but also maintains the walls of the jacket at substantially uniform temperatures throughout, regardless of the greater circulation of air at some points than others. i

I am aware that air cooled engines having external radiating fins formed on the cylinders have been used in conjunction with incl'osing-casings havingair exhaust fans or blowers for producing a forced circulation 'uneven cooling not only produces an internal stress in the metal due to the uneven expansion and contraction, but the excessive heat in spots interferes with the lubrication, causing the cylinders to score, and `otherwise. deranging the motor.

With my improvement this defect ofthe air circulating systems heretofore unavoidable is done away with because the temperaturevof the cylinder wall is determined solely by the inclosed liquid, the temperature of which is substantially uniform as it is determined by the average radiating capacity of the jacket as a Whole.

.Instead of employing a single, outer casing 10 as indicated in Figs. 1 and 2, the casing may be divided into upper andv lower halves 13 and 14, as shown in Fig. 3, surrounding the side walls and top` of the water jacket, respectively. Each casing may have its scparate exhaust connection as indicated at l5. and 16, and an air intake opening 17 Will be provided between the two parts o f the easing. If desired, also the casing may be divided vertically into separate sections for each cylinder as shown in Fig. 4, each sep-' arate compartment 18 having its individual exhaust connection 19. L

In this design the radiating fins on the casing wall will preferably extendvertically along `the side walls and radially across the top, converging atv the center of the cylinder head beneath the exhaust opening. The structure may obviously be otherwisemodified in its details, for instance, instead of a suctionffan, a blower could be used to circulate thc air through the casing.

- In the. foregoing description, where I have referred to the substance in the jacket as water, I havexused the word as a generic term for substances liquid at the temperature of operation of the motor and notin a limiting sense. In fact, in most instances it will be preferable to usesubstances of higher boiling points than water, as engines operate 75 of air around the cylinders. Such devices f avoids the difficulties incidental to the water in cold weather, andmore eiciently and the combustion is more perfect at higher temperatures than can be obtained without boiling the water.

The substance in the jacket may be liquid at' ordinary temperatures, such as suitable salt solutions, or glycerin or oils of high boiling points, but I prefer to use a substance which is solid at ordinary temperatures but of low melting point so as to be liquid at the operating temperature of the engine, such for instance, as paraffin or metal alloys of low melting point.

The use of a substance of this character possible freezing 'of also has the additional advantage that when the engine is cold and just being started the substance is solid and will therefore have comparatively little cooling effect, thus allowing the engine to be gotten up to normal running conditions much more rapidly than with Water or other substance liquid at normal temperatures. Also the engine will keep Warm a much longer time after it is stopped as the substance will solidify on the outside Wall of the jacket as it cools, thereby reducing its heat absorbing capacity.

I claim:

1. In an internal combustion engine the combination of a plurality of cylinders each having a portion forming an explosion chamber, a single jacket for all said cylin- :lcrs forming with the cylinder walls a fluid jacket, an inclosing casing tight chamber surrounding the explosion chambers, a substance in said chamber which is liquid at o erating 4temperatures and adapted to free y circulate by convection in said chamber for transferring the heat from the cylinder walls to the outer wall of the g surrounding said jacket and spaced therefrom, and means for maintaining an air circulation throu yh the casing to absorb the heat from the sur ace of the jacket.

2. In an internal combustion engine the combination of a plurality of cylinders each having a portion forming an explosion chamber, a single jacket for all said cylinders formiii with the cylinder walls a fluid tight cham er surrounding the explosion chambers, a substance in said chamber which is liquid at operating temperatures and adapted to freely circulate by convection in said chamber for transferring the heat from the cylinder walls to the outer wall of the jacket, an inclosin'g casing surrounding said jacket and spaced therefrom, and means for maintaining an casing to absorb the heat from the surface of the jacket, said casing being divided into sections to thereby more uniformly distribute the air over thyA surface of the jacket to be cooled.

In testimony whereof I aiiix my signature.

ADOLF J. MARSCHALL.

air circulation through the 

